Automobile control.



No'. 852,728. PATENTBD MAY '7, 1907.

y H. LEMP.

AUTOMOBILE CONTROL.

APPLIOATION FILED 001211. 1905.

2 SHEETS-SHEET 1.

PATENTE) MAY 7, 19,0?.

H. LEM?. AUTOMQBILE CONTRO APPLICATION FILED 00T.11, 1905.

2 SHEETS-BHEET 2.

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p\L. @L DL X @l mm w H thereof.

` UNITED srnrns HERMANN Leur, Or LYNN, Massa Specification of LettersEatent.

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cnolsnrrs, .fissrenon ro Gennaio'. n eonronnfrion or New vonk.

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Eatented ilay "Y, 3.907.,

Application filed Getober ll, 1905. Serial No. 282,238.

To .mZ/l wil/mit t may cmi/cern:

-Be it known that l, HERMANN Liner, a' citi- Zen of the UnitedStates,residing at Lynn, county ot Essex, State ot Massachusetts, haveinvented. certain new and useful lmprovements in Automobile Control,` oiwhich Vthe following is a specification.

My invention relates to the control oi' au tomobiles oi the type inwhich the drivingwheels are independently rotatable and are,

driven by independent series-wound electric motorsg. and the object otmy invention is to provide .novel connections for electrically brakingthe vehicle in such a manner es to prevent skidding.

.lt has been proposed heretofore to brake vehicles driven byseries-wound electric motors by short-circuiting the motors through aresistance -with the connectionsof `iield and armature relativelyreversed. ",lhis method- 'Ot braking with the connections heretotorcemployed tends to produce ,skiddin'g when applied to a vehicle withindependently rotatable driving-wheels on opposite sides lt the motorsare connected in series, the currents iiowing through the Alields andarmatures oi both motors are at all times equal, so that the. torques ofboth motors are equal without regard to their relative speeds.

Consequently, it one driving-wheel is passino over a slippery spot inthe road, skidding or that wheel may be produced. @n the other hand, itthe motors are connected in parallel, and short-circuited through aresistance, the currents through thetwo motors are not necessarily thesame, so that their speeds and torques may be unequal, and' aninequality in field strength Ot the motors, arising lrom any cause, willbe in itself a source ot skidding.

My invention consists inarranging the controlling switch tOshort-circuit the motors through a resistance with their iields inseries and with their'armatures in parallel. lilith this connection thesame current must always flow through both fields, so that the`lield-'strength of the two motors are malintained equal, and since thearmatures are connected in parallel, any di'llerence in their speeds,such as would arise `from a tendency of one wheel to slip, will producea dillerence in the electroinotive forces induced in the armatures. Theinequality in the electromotive forces in the two armatures will tend tocause current to tlow in the shortcircuit l" niiied.by the twoarmatures, and this cur- 55 'mechanically connected thereto, of aresistance and a controlling switch adapted to shorteeircuit the motorsthrough the resistH ance withtheir iields in series andtheir armaturesin parallel` p My invention will best be understood by reference to theaccompanying drawings, in which l shows a plan view, with the ear bodyremoved, of an automobile adapted to be controlled in accordance with myinvention; l? ig. 2 is a diagram Oi the connections oll the controllingswitcl'i; and Fig. 3 is a diagram et the motor connections produced hythe controlling switch ol Fig. 2.

ln the drawings, G represents a source of electric current, such asgenerator driven by an engine E and supported on theI trame lll of thevehicle. f

Wl and lll represent the driving-wheels ol' the vehicle, which areindependently sleeved on the rear axle A in the usual manner, so as tobe ii'nlependently rotatable.

M and M rein'eseut two series-wound electric motors, each ol'. which isconnected mechanically to one ot the driving-wheels through suitablegearing.

ln llig. 2 the generator is shown-as a coinpmmd-wouiid machine having ashunt -lield f and a series' lield f. Y l prt to employ acompi)und-wound generator, since it permits oi control over wide rangesby varying the speed of the prime mover, as a compoundwound generatorvwill operate over wide nges ot speed and widely varying load withoutlosing its excitation.- ln Fig. 2 the 'FieldsV oi the motors M and M arerepresented by the letters m and m, respectively. .lt repre` sents aresistance through which the motors and which is shown as having tivepositions indicated by the dotted lines 1X to 5X, respec- `generator inparallel as shown in diagram 1X of Fig. 3. This is thehigh-speed'forward running position. ln the position 2X of switch S themotors are connect-ed,in series, as shown in diagram 2X ol' Fig. 3. Thisis the low speed vforward running position. 'Position BX isthe coastingposition lier torward running -and the braking position for baekwardrunning. In this position of the controlling switch the generator isopen-circuited and the motors are short-circuited through a resistancelt, the 'fields being in series and tl armatures being in parallel.

lt will be noted that the relative connections ot the lield and armatureof each motor are the. same as in diagrams l.X andQX, so that no brakingell'eet is produced tor Yforward ruiming. Position 41X is the positionfor braking tor l'orward running.- As in position 3"", the. motors areshort-ci'reuited through the resistance R with the I'ields in series andthe armatures in parallel, but the relative connections ol tht Ylieldand armature ot each motor are reversed with respect to the connectionsolf position 3X. In position 5 the motors are connected in series to thegenerator, but with lields and armatures relatively'reversed withrespect to position 2K. This the position lor backward running. i

With the braking comreetions shoum, the 'held strengths olV both motorsare-at all times equal, and since the armatures are connected inparallel so that the two armatures lorm a short-circuit tor each other,anyditl'erenee in induced electromotive loree. due to one armatureruiming at a higher speed than the other, will strengthen the current inthe armature ru'nning at the higher speed and seep/ee weaken the currentin the armature running at the lower speed-that is7 the torque on theformer motor Will be increased and that onthe latter motor (,lecreased,so as automatically to bring the motors back to the same speed, and inthis manner the tendency to skid is automaticallyr compensated for,since the motors, and consequently the drivingwheels, are kept ri'inningat the sainespeed.

by Letters Patent of the United States, is,-

.1. In an electrically-driven vehicle, independently rotatabledriving-Wheels on oppo sitel sides of the Vehicle, series-wound electricmotors mechanicallyT connected to said wheels, a resistance, and acontrolling switch adapted to connect the motors in short-circuitthrough said resistance and with the motor ields in series and armaturesin parallel. i i

2. In an electricallydriven Vehicle, independently rotatabledriving-wheels on opposite sides ot' the vehicle, serieswound electricmotors mechanically connected to said wheels, a resistance, andacontrolling switch adapted to connect the motors to a source ol currentineseries and in parallel l'or ditl'erent speeds and` to short-circuitthe motors through said resistance for braking with the motor fields inseries and armatures in par allel. 3. ln an electrically-driyen vehicle,independently rotatable drivingfwheels on opposite sides ot the vehicle,series-wouml electric motors mechanically, connected to said wheels, asource ot current i'or said motors carried by the vehicle, a resistance,and a controlling switch adapted to connect the motors in series and inparallel to said source and to short-cireuit the motors through saidresistanee with the motor lields in series and armatures in parallel. iln witness whereol', i have hereunto set my hand this sixth day otOctober, 1905.

i l'lERlliANN LEMP.

`ilVitnesses:

Jona' A. MeMANUs, Jr., HENRY O. WEsTENnARr.

What l. claimas new, and desire to secure

